Acacias of Australia

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Acacia megalantha F.Muell.




Occurs near Mount Isa, Qld, and in the Arnhem Land ranges (and Victoria River region), N.T., S to the east Kimberley region, W.A.


Resinous shrub to 4 m high. Bark ±smooth, grey. Branchlets ±flattened towards apices, orange-brown, squamulose. Phyllodes narrowly elliptic or elliptic, often oblique, (4–) 5–11 (–13.5) cm long, (10–) 14–28 mm wide, coriaceous, rigid, mostly with 3 prominent longitudinal nerves; minor nerves (2–) 4–6 (–7) per mm, longitudinal, normally non-anastomosing except at apex and base; gland 1, basal, inconspicuous. Spikes 1.4–3.5 (–5) cm long, golden. Flowers 5-merous; calyx 1.1–1.5 mm long, dissected to 1/4–1/3, sometimes squamulose or slightly hairy; corolla 2.9–4 mm long, dissected to 7/12–4/5, glabrous; ovary tomentose. Pods ±straight-sided, ±straight to curved, flat, 3–10 cm long, (6–)_7.5–11 mm wide, woody, glabrous; margins pale, thick. Seeds longitudinal, orbicular to broadly elliptic, 4.8–6.2 mm long, light brown, minutely pitted; pleurogram prominent; areole closed, light- to mid-brown.


Flowers Apr.–Sept.


Grows on sandstone, in shallow soil on rocky hillsides and plateaux in eucalypt-spinifex woodland.


W.A.: Helicopter Spring, South Turkey, I.Cowie 1880 (CANB, DNA, PERTH). N.T.: 25 km WNW of Twin Falls, Kakadu Natl Park, L.A.Craven 6230 (CANB, NSW); Koolpin Gorge, C.Dunlop 3600 (DNA, NSW); Keep River Natl Park, C.Dunlop 5822 (DNA, NSW); range E of UDP Falls, C.H.Gittins 2614 (NSW). Qld: 27.2 km from Mount Isa on Camooweal road, C.H.Gittins 750 (NSW); Lake Moondarra, Mount Isa, R.G.Coveny 477 (NSW).


The large individual flowers on interrupted spikes are distinctive, as are the faint transparent longitudinal nerves in the corolla. The specimen ‘Keep R., N.T., A.S.Mitchell 326 (DNA)’ has large phyllodes (to 13.5 cm long) and spikes (to 5 cm long, 12 mm wide). The minor nerves on the phyllodes of plants from Qld are more widely spaced (2–4 per mm) than elsewhere (4–7 per mm).

FOA Reference

Data derived from Flora of Australia Volumes 11A (2001), 11B (2001) and 12 (1998), products of ABRS, ©Commonwealth of Australia


Dr M.D.Tindale and Dr P.G.Kodela with the assistance of M.Bedward, S.J.Davies, C.Herscovitch, D.A.Keith and/or D.A.Morrison

Minor edits by B.R.Maslin & J.Rogers